The risk of an adverse reaction should always be carefully weighed against the benefit expected to be obtained from a contrast enhanced imaging examination.

Ensure appropriate consent, screening procedures including risk assessments and precautions are in place for all patients when IV contrast is to be administered.

Early recognition of the signs and symptoms and timely management of adverse reactions is important and may prevent the reaction from becoming severe or life threatening.

Most immediate hypersensitivity adverse reactions occur within the first 60 minutes after IV contrast administration, with the greatest risk in the first 10 minutes after administration.r

Non-vascular administration of contrast media (e.g. oral contrast) also has a risk of anaphylactic reactions. Whilst this is rare, the appropriate precautions should be taken as with IV administration.

For patients at an increased risk of CI-AKI and lactic acidosis, ensure an eGFR has been performed and checked by a medical professional or nurse prior to IV contrast administration as per institutional guidelines.

The purpose of this information is to provide guidance to health professionals in the administration of contrast for radiotherapy simulation scans. Only health care professionals who have attained competency in intravenous (IV) cannulation and administration of contrast as per institutional guidelines should perform the included procedures. This document should be used in conjunction with expert clinical judgement and with individual institutional guidelines or policies.

The health care professional administering IV contrast should follow the relevant national and local institutional guidelines for the safe administration of IV contrast. They should be trained and competent in the relevant procedures including intravenous cannulation, IV contrast administration, the recognition of contrast media reactions, appropriate management, and resuscitation procedures including basic life support and have rapid access to staff competent in advanced life support. Administration of contrast should be in line with the relevant manufacturers’ product information and the TGA requirements including contrast media use, bottles/containers, syringes and all other components of the contrast delivery system.r

Radiocontrast can be administered intravenously to enhance the visibility of vascular structures and organs during medical imaging procedures. There is a risk of adverse reactions to IV contrast administration. Adverse reactions include immediate and delayed hypersensitivity reactions, renal adverse reactions and extravasation.

Hypersensitivity reactions can be immediate or delayed. Immediate reactions occur within 1 hour of IV contrast administration and can be classified as mild, moderate or severe and can be life threatening.rDelayed reactions occur between one hour and one week after IV contrast injection.

Renal adverse reactions include contrast induced acute kidney injury (CI-AKI) and lactic acidosis. Patients with severe renal function are at the highest risk of CI-AKI. Lactic acidosis is a medical condition characterized by the build-up of lactate in the bloodstream.

Identification of individuals at increased risk of an adverse reaction and the application of appropriate preventative measures is considered the best management approach. The risks and benefits of the IV contrast procedure should be considered in all patients.

Hypersensitivity adverse reactions

In patients identified as having an increased risk of an anaphylactic reaction consider the risks and benefits of the procedure and alternatives including performing a non-contrast media study or other imaging modalities not requiring iodinated contrast.

If the decision is made to proceed with the iodinated contrast media procedure in a high risk patient RANZCR recommendations include:r

use a different non-ionic low or iso-osmolar contrast media to the one used previously in the setting of a prior reaction if possible

maintain close medical supervision

leave the cannula in place and keep the patient under observation for 30 minutes after contrast media administration

ensure emergency drugs and equipment for resuscitation are readily available

be prepared to treat any adverse reaction promptly

consider use of premedication with corticosteroids (+/- antihistamines) as it has been shown to reduce the likelihood and severity of anaphylactic reactions. There is no evidence that it reduces the likelihood of death resulting from a breakthrough anaphylactic reaction.

Renal adverse reactions

RANZCR recommend that, regardless of renal function status, any patient should be given IV contrast if, in the opinion of the radiologist and the referrer, there is a perceived diagnostic benefit to the patient to justify its administration.r

Not all patients having IV iodinated contrast require pre-administration testing of their renal function. An eGFRshould be obtained prior to IV contrast administration in patients with any of the following:

known kidney disease (including kidney transplant)

diabetes

currently taking a drug containing metformin.

It is rare that severe renal impairment is not identified prior to IV contrast administration as it is uncommon that patients are unaware that they have either diabetes or kidney disease.r Additional factors to consider include dialysis status, age, time between renal function testing and IV contrast administration.

Prevention of CI-AKI and hydration/fluid administration

The following table on the risk of CI-AKI and special precautions are based on RANZCR recommendations:r

eGFR

Risk of CI-AKI

Special precautions

>45 mL/min/1.73 m2

Likely non-existent

No special precautions before or after IV contrast administration are recommended

30 - 45 mL/min/1.73 m2

Very likely to be low or non-existent

General use of periprocedural hydration in this group isn’t recommended.

However, patients with impaired function in this range that are acutely deteriorating rather than stable may benefit from periprocedural hydration

<30 mL/min/1.73 m2 (Severe renal function impairment)

OR

Actively deteriorating renal function (acute kidney injury)

Risks versus benefit of IV contrast administration needs to be considered

Consider periprocedural renal protection using IV hydration

Severe renal function impairment should not be regarded as an absolute contraindication if IV contrast is medically indicated

Periprocedural hydration

For patients at higher risk of CI-AKI, periprocedural IV volume administration is recommended, and the type of solution may be important. If there are no contraindications to volume expansion, it is recommended that isotonic intravenous fluids be used prior to, and for several hours after, contrast administration.r

Timing and rate of administration are independent of fluid type and vary between inpatients and outpatients. Examples of reasonable fluid regimens can be found in these guidelines:

These recommendations for hydration do not apply to patients under fluid restriction, e.g. patients with congestive heart failure (CHF) or on dialysis.

There is no substantial evidence that oral hydration has any effect on the incidence of CI-AKI as a substitute for IV hydration.

Acetylcysteine

The benefit of the administration of acetylcysteine to prevent CI-AKI remains uncertain, and comparison of the various trials is difficult because of differences in patient populations and dosing or lack of an adequate control group.r

Based upon the lack of convincing evidence of benefit, potential risk of anaphylactic reactions and cost, intravenous acetylcysteine is not recommended.r

Volume depletion and NSAIDs

The avoidance of volume depletion or nonsteroidal anti-inflammatory drugs (NSAIDs) is advised as both can increase renal vasoconstriction.

Adverse reactions to IV contrast can be severe and life threatening.
In an EMERGENCY call the EMERGENCYTEAM per institutional policy.

Patients should be continuously monitored during contrast administration to ensure contrast is being injected correctly and assess for any signs of adverse reaction including anaphylaxis. Adverse reactions may be life threatening and a delay in recognition of initial signs and symptoms and initiating appropriate responses can result in a fatal outcome e.g. as a result of airway obstruction or vascular collapse. If a patient has a hypersensitivity reaction or extravasation immediately cease the procedure and follow appropriate management of these.

Immediate hypersensitivity adverse reaction assessment

Immediate hypersensitivity adverse reactions resulting in anaphylaxis may be mild, moderate or severe. Most immediate hypersensitivity adverse reactions occur within the first 60 minutes after IV contrast administration, with the greatest risk in the first 10 minutes after administration.r

The following table on classification and signs and symptoms of a hypersensitivity anaphylactic reaction are based on RANZCR recommendations.r

Delayed hypersensitivity adverse reaction assessment

Delayed hypersensitivity adverse reactions usually involve skin reactions and are not usually associated with bronchospasm or laryngeal oedema.r Maculopapular rash is the most common reaction with less common delayed reactions including angioedema, urticaria and erythema.r

Extravasation assessment

Signs and symptoms of extravasation include pain, swelling, discomfort, redness, burning, or stinging at the site of IV contrast administration.

Adverse reactions to IV contrast can be severe and life threatening.
In an EMERGENCY call the EMERGENCYTEAM per institutional policy.

Management of hypersensitivity reactions

The appropriate drugs and equipment, and institutional policies and procedures to respond to an anaphylactic emergency should be in place prior to IV contrast administration. For example recommendations of emergency trolley contents see link to RANZCR - Iodinated contrast media guidelines 2016 (Section 3.4)r

The management of anaphylactic hypersensitivity reactions is based on the severity of the reaction. Moderate to severe anaphylactic reactions can be life threatening and should be considered a medical emergency. A delay in the initiation of treatment such as adrenaline can result in deterioration and death of the patient. In an emergency follow institutional policies and procedures.

Contrast and flow rates for injection of contrast media

The volume of contrast and the flow rate at which it should be administered for each CT/MRI scan procedure should be determined prior to administration through consultation between the contrast company representative, the hospital’s diagnostic department and the radiation oncology department. Factors that will affect these decisions are:

type/brand of contrast used

the osmolarity of the contrast

viscosity of contrast – this will affect the flow rate at which the contrast can be injected

structures to be highlighted on CT/MRI scan

integrity of patient veins.

Contrast media storage, warming and disposal

Contrast media should not be stored long-term in the contrast warmer. The ideal contrast warmer temperature is 37°C. Unused portions of opened contrast media and used containers and equipment should be disposed of as per institutional guidelines.

Use of central venous access devices (CVADs)

Most central venous access devices (CVADs) are designed to withstand up to 40PSI. Power injectors generate pressure in a catheter higher than 40PSI; therefore, damage and rupture of a catheter may occur if a standard CVAD is used for the administration of IV contrast with power injections.5 The administration of IV contrast through a standard CVAD is not recommended.

There are power injectable CVADs available which have been designed to tolerate the pressures required for the injection of IV contrast, but these are not routinely used. It is essential to correctly identify if a CVAD is power-injectable before using it for a power injection. Each individual device will have identifiers that confirm the CVAD is suitable for power injections. These identifiers will differ depending on the device. The presence and type of CVAD should be documented in the patients’ records. It is important to verify with the patient and patient records what type of CVAD or port they have in situ (i.e. low pressure or power) before they are used to administer IV contrast via a power injector.

Explanation of the common sensations patients experience during IV contrast administration, and reassurance that they are only temporary, such as a warming sensation through the body, metallic taste in the mouth and a sensation that they have passed urine.

Explanation of the need for risk determination and management regarding

hypersensitivity reactions

renal risk factors

other medical risk factors.

Educate the patient on signs and symptoms of an anaphylactic reaction or extravasation.

Inform the patient to immediately notify staff if they experience any of these during or after the contrast administration.

Metformin recommencement

Patients who are required to cease Metformin should be given information on the recommencement of Metformin 48 hours after the contrast scan (where appropriate as per institutional guidelines) and also provided with a letter to GP if required.

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Version 3

Date

Summary of changes

30/11/2011

Approved for publishing on eviQ

24/01/2012

Under Contrast Administration Procedure section - removed recommendation to cannulate in dorsum of hand and replaced with "ensure cannulation site is in a suitable position to perform the CT scan, taking into consideration patient position".

Reviewed and approved for publishing on eviQ. Version number change to V.3.

This document reflects what is currently regarded as safe practice. While every effort has been made to ensure the accuracy of the content at the time of publication, the Cancer Institute NSW does not accept any liability, with respect to loss, damage, injury or expense arising from any such errors or omission in the contents of this work. Any reference throughout the document to specific pharmaceuticals and/or medical products as examples does not imply endorsement of any of these products. Use is subject to eviQ’s disclaimer available at www.eviQ.org.au